bsybiofandomcom-20200214-history
Chapter 18 G.4 Conservation of Biodiversity
What is an indicator species, and what can we do with them? An introduction to Biotic Indices. Indicator species: a species which is more sensitive to changes in the environment (and thus indicates ''them) ''Biotic index: a measure of the health level of a water body, found by counting the number of different populations, each count given a different weight depending on its sensitivity What contributes to extinction? Example of the Caroline Parakeet: : The Carolina Parakeet is a brightly coloured bird found throughout the United States. It nested in large groups in hollow trees, often remaining together. As settlers spread into the west in the mid 1800s, large areas of trees were cleared, effectively destroying the Parakeet’s habitat. However, more than just habitat destruction was responsible. Hoey bees, from Europe, quickly began to invade the Parakeet’s habitat. Furthermore, parakeet feathers were sought after by hatmakers. A combination of these factors led to their extinction in 1900. Features of reserves which promote biodiversity: *'Size': a large size gives organisms sufficient area to have large populations, which allows for greater variation and thus less chance of extinction. Furthermore, larger areas have smaller relative edges, where species are vulnerable to predation and competition. *'Edge Effects': the edge is a unique area for species to develop, since certain resources may be higher and others lower. The native species of the reserve face competition here, and the competitors have an opportunity to thrive. *'Corridors': a corridor connects two habitats, allowing for the flow of species between the two. It is useful in, for example, connected farway habitats of endangered species, resulting in greater interaction and hopefully population. Managing Conservation Areas *'restoration': attempts to restore habitat to completely untouched state - levels of vegetation, etc. *'recovery': threatened species affected by an unfair tip in competition need active aid to be recovered to their natural status *'removal': introduced invasive species need to be eliminated before they can take over the habitat by themselves - this is a necessary step, since invasive species can be devastating to a habitat *'legal protection and funding': cordoning the area off from human intervention, as well as pumping financial resources to stimulate all the above restoration efforts, is necessary to effective active restoration. In Situ Methods of Conservation: *protecting targeted species by maintaining habitat *defending from predators *removing invasive species *maintain reserve size to allow for population size equilibrium *maintain population size to allow for genetic diversity Ex Situ Methods of Conservation: *'Captive Breeding' is the growth of a population in captivity, safe from its natural predators and dangers. Zoos often have many captive breeding programs. However, this can be harmful - disease can spread quickly, and lessons learned in the wild never are. *'Botanical Gardens' are another method of ex situ conservation - plants bred in captivity. It is easier to care for them, and experience in the wild is not an issue. However, plants in the wild of the same species may be missing out on immunities that the captive plants hold. *'Seed banks' are another method - seeds of species are preserved in cold, dark areas where they don’t germinate. Around 10,000 to 20,000 species are preserved in this way.